Nuclear magnetic resonance vs. computed tomography.

The diffusion of computed tomographic (CT) scanners into the health care system, after an initially torrid start, eased up considerably once the diagnostic capabilities of the revolutionary devices were recognized. In the estab lishment of the scanners in the medical community , comments such as " definitive and conc lusive diagnosis ," " value clearly demonstrated ," and " prevention of deaths and disabi lity with relief of pain and suffering " were used frequently and enthusiastically. The ultimate accolade awarded to CT scanning was surely the Nobel Prize in Physiology or Medicine in 1979. In light of this award, the phrase, " the greatest benefit for mankind," is applied . Certainly, no physician can criticize CT scan ning as not being a boon to medicine. Nuclear magnetic resonance (NMR) has now burst on the scene with an excitement on ly matched by that experienced in the last decade with CT. While NMR is still in its infancy, it has jumped the two hurdles of " how well does it work? " and " can you see someth ing worth seeing? " to " how does the new technology compare with the old?" The few medical centers now doing clinical trials are starting to grapple with sensitivity and specificity , and ultimately the question of utility will come into the picture. At the recent meeting of the XII Symposium Neuroradiologicum at Washington, DC, in October 1982, a strong sense of " deja vu " existed as the various speakers extolled the merits of NMR. Again, the terms " more sensitive, " " less invasive, " and " phenomenal abi lity " were heard , but this time with a difference. Instead of comparing the new modality with the painful , dangerous, comparative ly high-radiation technologies such as angiography and pneumoencephalography, the wonder child , CT scanning, was under fire! It is natural and appropriate that one noninvasive modality be compared with another. Only by carrying out this type of